Accumulation Weather Parameters: Rain, Snow, Sleet (Core Layer, Included)

Tomorrow.io provides detailed accumulation data for all major precipitation types, helping users interpret and act on rain, snow, sleet, and ice impacts across operational scenarios. This data is essential for forecasting disruptions, informing safety protocols, and planning around weather-driven risks.

🌐 This is a core platform and API feature available to all Tomorrow.io users.

Overview of Precipitation Accumulation

Precipitation types tracked include:

• Rain
• Freezing Rain
• Ice Pellets (Sleet)
• Snow

How Accumulation Is Calculated

• Hourly measurements are used
• Past data is based on observations
• Nowcast and forecast data use predictive models
• Each type is tracked independently, maintaining clarity and avoiding misleading combinations

Liquid Equivalent Method

Tomorrow.io uses liquid equivalent values as the basis for measuring precipitation intensity and accumulation. This approach ensures consistency across different precipitation types and aligns with industry standards.

Snow Accumulation vs. Snow Depth

Snow Accumulation

• Definition: Measures how much new solid snow is falling during a forecast window
• Excludes: Sleet, ice pellets, freezing rain
• Use Case: Best for displaying forecasted snowfall amounts in both hourly and daily formats

⚠️ Avoid combining snow with sleet or freezing rain in display fields or alerts. These have different physical impacts and safety implications.

Snow Depth

• Definition: Reflects the total snow on the ground, factoring in compaction, melt, and new snowfall
• Timeframe: Available for both current conditions and forecast periods
• Use Case: Indicates how long snow will remain on the ground and how deep it is expected to get

Displaying Snowfall in the Platform

• Use Snow Accumulation to show hourly or daily snow totals
• Use Snow Depth to reflect real-world snowpack conditions
• Avoid mixing solid and non-solid precipitation in displays (e.g., don’t combine snow with freezing rain unless explicitly required)

Learn more about using accumulation tiles in your map display.

Handling Mixed Precipitation Types

In some hours, multiple precipitation types may occur (e.g., snow + sleet). However:

⚠️ For clarity and user safety, always separate precipitation types in insights, reports, and alerts.

This avoids confusion and ensures accurate representation of weather impact.

Recommendations

For best practice:

• Use Snow Accumulation to show new snowfall amounts
• Use Ice Accumulation (for sleet or freezing rain) in a separate field
• Use Snow Depth to communicate lingering snow impact on surfaces

Need Help?

For questions or help integrating weather data, contact support@tomorrow.io or reach out to your Account Team.